[1] Metaphorically, "walled garden" may be used in many contexts (often pejoratively) to indicate a space, usually not a literal physical location, which is or is seen as closed to outsiders.
The shelter provided by enclosing walls can raise the ambient temperature within a garden by several degrees, creating a microclimate that permits plants to be grown that would not survive in the unmodified local climate.
The gardeners make the most of the northern or southern exposures and the permanently shady areas of this little, sheltered valley.
This kind of hollow wall is found at Croxteth Hall in Liverpool (England), and Eglinton Country Park and Dunmore House, both in Scotland.
At Croome Court an 18th-century cavity wall had a number of small furnaces to supply gentle heat (see below).
[3] The largest gardens served extremely large households, for example, the royal kitchen garden at Windsor was built for Queen Victoria in 1844 and initially occupied twenty two acres, but was enlarged to thirty one acres to supply the growing household.
[citation needed] In the story of Susanna and the Elders, a walled garden is the scene of both an alleged tryst and an attempted rape.
[10] In The Last Enchantment, the third book in Mary Stewart's novels of the Arthurian legend, Merlin constructs a heated wall for his garden at Applegarth.